Charging system problem

I have a 95 Tauras Wagon, and a couple of weeks ago I had to wash the engine, and made the mistake of not leaving the engine running while I washed it. I went to pick my wife up at work and while the engine was idleing, I noticed all my lights were pulsing, then brightened up when I reved the engine or turned on the heater.

For the next week when I started to accelerate onto the Interstate all my lights would dim and heater would slow down, then would brighten back up when I quit accelerating. This progressed to the point they would not brighten untill I slowed down on the off ramp. 2 days ago my battery light started to flicker at 35 mph. We took the car to Big O's yesterday and at first they said the alternator was not charging, then all of a sudden it was. We drove the interstate and around town today and the light never came on. Tonight when I left work my lights dimmed and heater slowed as soon as I turned onto the street and the indicator stayed on solid quite a few times for long periods of time all the way home.

I should also note that I have had the car for three years and when we come home at night the lights have always momentaraly dimmed when we exit the offramp and brake to stop. Battery, Alternator or Regulator.
I am not very good with cars so any help I get would be great.

you have bad volt regolatot mounted next to battary need to be replaced